The present invention relates to a flexible interconnect substrate, a film carrier, a tape-shaped semiconductor device, a semiconductor device and a method of fabrication thereof, and a circuit board, together with electronic equipment.
The tape automated bonding (TAB) method is known in the art for mounting semiconductor chips auto a flexible interconnect substrate. Leads are formed on the flexible interconnect substrate and these leads are connected to pads of the semiconductor chips.
With this TAB method, the flexible interconnect substrate is curved and reel-to-reel processing is performed thereon, but when such a flexible interconnect substrate is wound onto a reel, the leads thereof may become bent.
The present invention was devised to solve this problem and has as an objective thereof the provision of a flexible interconnect substrate, a film carrier, a tape-shaped semiconductor device, a semiconductor device and a method of manufacturing the same, a circuit board, and electronic equipment that make it possible to prevent bending of the leads.
(1) A flexible interconnect substrate in accordance with the present invention comprises: a tape-shaped base substrate; and an interconnect pattern formed an the base substrate,
wherein the base substrate includes: a first region in which a predetermined interconnect pattern has been formed and which will form a unit when separated from the base substrate; and a second region positioned next to the first region in the longitudinal direction of the base substrate; and
wherein the second region has a low-bending-resistance portion which is formed in a region that excludes a central portion of the second region in the widthwise direction of the base substrate, for ensuing that the second region bends more readily in the direction in which the longitudinal axis of the base substrate bends, in comparison with the first region.
This aspect of the present invention ensures that a region (a second region) that is designed to bend more readily is provided adjacent to a region (a first region) that is to be punched out. When the flexible interconnect substrate is bent, stresses therefore concentrate in this second region, and thus the stress concentrations avoid the first region. This suppresses any bending of the interconnect pattern within the first region.
In addition, the low-bending-resistance portion is formed in a region that excludes the central portion in the widthwise direction of the base substrate within the second region, making it possible to suppress excessive deformation of the second regions, even when the base substrate in pulled in the longitudinal direction.
(2) In this flexible interconnect substrate,
the low-bending-resistance portion may be one of through-holes, cuts, and a thinner portion.
A thinner portion makes the bending resistance lower, and through-holes or cuts reduce the bending resistance to zero. Thus the term xe2x80x9clow-bending-resistance portionxe2x80x9d includes any portion where the bending resistance is zero.
(3) In this flexible interconnect substrate, the configuration may be such that.
a high-bending-resistance portion in formed in each of the first region and the central portion of the second region in the widthwise direction of the base substrate;
the high-bending-resistance portion in formed to avoid a region that excludes the central portion of the second region in the widthwise direction of the base substrate; and
the region avoided by the high-bending-resistance portion forms a relatively low-bending-resistance portion.
This configuration is not limited to a case in which the low-bending-resistance portion in formed deliberately; it could also apply to cases in which the bending resistance in reduced by an increase in the bending resistance in all other portions.
(4) In this flexible interconnect substrates the configuration may be such that:
a hole is formed in the first region of the base substrate; and
a portion of the interconnect pattern is positioned within that hole.
With this configuration, the portion of the interconnect pattern that is positioned within the hole is not supported by the base substrate, but since the stresses concentrate in the second region, as described above, the bending of a lead that is positioned within the first region is suppressed.
(5) In this flexible interconnect substrate,
the second region may be formed to bend more readily than the first region that bends readily due to the formation of the hole.
The formation of the hole makes it possible for the first region to bend more readily, but the second region bends even more readily than that first region, making it possible to avoid stress concentrations in the first region.
(6) In this flexible interconnect substrate,
a plurality of the low-bending-resistance portions may be formed in a straight line within the second region, across the width of the base substrate.
This makes it easier for the second regions to bend.
(7) In this flexible interconnect substrate,
the plurality of low-bending-resistance portions may be disposed on two edge portion sides of the base substrate, symmetrically with respect to the center in the widthwise direction of the base substrate.
This ensures that the substrate bends readily in a manner that is symmetrical across the width thereof.
(8) In this flexible interconnect substrate,
the plurality of low-bending-resistance portions may be disposed on two edge portion sides of the base substrate, asymmetrically with respect to the center in the widthwise direction of the base substrate.
This makes it possible to ensure that the substrate bends readily in a manner that is asymmetrical across the width thereof.
(9) In this flexible interconnect substrate,
the interconnect pattern may be formed to be offset towards either of two edge portions of the base substrate, with respect to the center in the widthwise direction of the base substrate.
This makes it possible to dispose the interconnect pattern in correspondence with a asymmetrical mode of bending.
(10) a tape-shaped semiconductor device in accordance with the present invention comprises the previously described flexible interconnect substrate; and a semiconductor chip connected electrically to the interconnect pattern of the base substrate.
With this aspect of the present invention, all the above described details of the flexible interconnect substrate apply.
(11) Another tape-shaped semiconductor device in accordance with the present invention comprises
the previously described flexible interconnect substrate; and
a semiconductor chip which in disposed offset towards either of two edge portions of the base substrate, with respect to the center in the widthwise direction of the base substrate, and which is connected electrically to the interconnect pattern of the base substrate.
With this aspect of the present invention, all the above described details of the flexible interconnect substrate apply.
(12) A semiconductor device in accordance with the present invention has a shape obtained by punching out the base substrate of the previously described tape-shaped semiconductor device along an outline that surrounds the semiconductor chip.
This semiconductor device is not limited to one obtained by punching out the tape-shaped semiconductor device as described above, but it can also apply to semiconductor devices that have the same configuration and shape as punched-out devices. Details of the flexible interconnect substrate are as described previously.
(13) A circuit board in accordance with the present invention is connected electrically to the previously described semiconductor device.
(14) Electronic equipment in accordance with the present invention comprises the previously described semiconductor device.
(15) A method of manufacturing a semiconductor device in accordance with the present invention comprises the steps of: winding the previously described flexible interconnect substrate onto a reel in preparation; and then pulling the flexible interconnect substrate out from the reel.
In this aspect of the present invention, the base substrate bends as the flexible interconnect substrate is wound up, but it is possible to suppress bending of the interconnect pattern because the previously described flexible interconnect substrate is used therefore.
(16) Another method of manufacturing a semiconductor device in accordance with the present invention comprises the steps or: winding a tape-shaped semiconductor device which comprises the previously described flexible interconnect substrate and a semiconductor chip connected electrically to the interconnect pattern of the flexible interconnect substrate, onto a reel in preparation; and then pulling the tape-shaped semiconductor device out from the reel.
In this aspect of the present invention, the base substrate bends as the flexible interconnect substrate is wound up, but it is possible to suppress bending of the interconnect pattern because the previously described flexible interconnect substrate is used therefore.
(17) In this method of manufacturing a semiconductor device, the flexible interconnect substrate may be punched out at the first region, during the step of pulling the tape-shaped semiconductor device out from the reel.